High-pressure viscosity of glycerol measured by centrifugal-force viscometry

Herbst, C. A.; Cook, Richard L.; King, H. E.

doi:10.1038/361518a0

Cited by 70 publications

(38 citation statements)

References 28 publications

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“…A complementary way to vitrify a liquid is by applying pressure. [8][9][10] In this way no kinetic energy is withdrawn from the system, but the energy barriers that connect different regions in configuration space are increased in height, and their spacing is decreased due to compression. For pressures higher than the glass transition pressure, the system is trapped between barriers.…”

Section: Introductionmentioning

confidence: 99%

Competition between vitrification and crystallization of methanol at high pressure

Brugmans

Vos

1995

The Journal of Chemical Physics

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Competition between vitrification and crystallization of methanol at high pressure Brugmans, M.J.P.; Vos, W.L. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. We have studied methanol at high pressure up to 33 GPa at room temperature with x-ray diffraction, optical ͑polarization͒ microscopy, Raman spectroscopy, and detection of hydrostaticity. A competition between crystallization and vitrification is observed when methanol is superpressed beyond the freezing pressure of 3.5 GPa: between 5.0 and 10.5 GPa crystals can nucleate, but if this region is surpassed quickly enough ͑within a few seconds͒, methanol remains amorphous. For the first time the nucleation rate and the crystal growth velocity have been studied as a function of pressure. These kinetic properties can be described by classical nucleation theory in agreement with, respectively, Turnbull-Fisher and Wilson-Frenkel type behavior using one and the same activated hard-sphere diffusion coefficient. The experimental nucleation rate and the crystal growth velocity are both effectively reduced to zero above 10.5 GPa, because the diffusion is suppressed. At these pressures methanol is compressed into a glass.

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Section: Introductionmentioning

confidence: 99%

Competition between vitrification and crystallization of methanol at high pressure

Brugmans

Vos

1995

The Journal of Chemical Physics

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“…This inflection might arise from a non-linearity of the volume with a change of pressure. 18 It has also been attributed to the pressure dependences of the compressibility and of the apparent activation energy at a constant volume. 16 The hybrid model (Eq.…”

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confidence: 99%

Communication: Inflection in the pressure dependent conductivity of the protic ionic liquid C8HIM NTf2

Thoms

Wojnarowska

Goodrich

et al. 2017

The Journal of Chemical Physics

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“…It is also an experimentally convenient sample: it has a high dielectric constant and does not easily crystallize. Moreover, some complementary high pressure data exist for glycerol [3,4,5,6]. These studies are principally isothermal experiments in which temperature is fixed and pressure is varied in discrete steps; as such, these data are not optimal for studying tempera- * Electronic address: win@physics.umass.edu † Electronic address: menon@physics.umass.edu ture dependence.…”

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confidence: 99%

Glass transition of glycerol in the volume-temperature plane

Win

Menon

2006

Phys. Rev. E

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We assess the relative importance of spatial congestion and lowered temperature in the slowing dynamics of supercooled glycerol near the glass transition. We independently vary both volume, V , and temperature, T , by applying high pressure and monitor the dynamics by measuring the dielectric susceptibility. Our results demonstrate that both variables are control variables of comparable importance. However, a generalization of the concept of fragility of a glass-former shows that the dynamics are quantitatively more sensitive to fractional changes in V than T . We identify a connection between the fragility and a recently proposed density-temperature scaling which indicates that this conclusion holds for other liquids and polymers.PACS numbers: 64.70. Pf, 77.22.Gm When a liquid is cooled below its melting point its viscosity increases very rapidly with decreasing temperature until it turns into a glass, with solid-like properties. For instance, glycerol, a typical glass-former, shows a remarkable increase in viscosity and relaxation time of 14 orders of magnitude as it is cooled from 350K to 180K at 1 atmosphere [1]. There are two broad classes of explanations for this rapid increase of viscosity. One set of ideas identifies density as the crucial variable, arguing that the constraints on molecular rearrangements imposed by the dense packing in a liquid progressively increase due to the thermal contraction that accompanies cooling, until finally all motions are arrested in the glassy state. By this argument, the driving force for the rapid increase of viscosity in the case of glycerol would primarily be the 10% decrease in volume upon cooling. The second class of explanations for the slowing dynamics emphasizes the role of temperature: lowered temperature renders molecules too inactive to move around and surmount the energy barriers that impede exploration of their environment. In order to resolve the issue of whether it is temperature, T , or volume, V , that is the dominant variable in this phenomenon, experiments are required that independently control these variables. However, data of this kind are relatively sparse [2]. The objective of the experiments reported in this Letter is to distinguish unambiguously the effects of constrained volume and lowered temperature, by using high pressure as a mean of independently changing the density of the liquid.Glycerol is a widely-studied glass-former with broad industrial use. It is also an experimentally convenient sample: it has a high dielectric constant and does not easily crystallize. Moreover, some complementary high pressure data exist for glycerol [3,4,5,6]. These studies are principally isothermal experiments in which temperature is fixed and pressure is varied in discrete steps; as such, these data are not optimal for studying tempera- * Electronic address: win@physics.umass.edu † Electronic address: menon@physics.umass.edu ture dependence. They also appear to disagree with each other on the temperature dependence of the relaxation frequency ν p near the ...

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High-pressure viscosity of glycerol measured by centrifugal-force viscometry

Cited by 70 publications

References 28 publications

Competition between vitrification and crystallization of methanol at high pressure

Competition between vitrification and crystallization of methanol at high pressure

Communication: Inflection in the pressure dependent conductivity of the protic ionic liquid C8HIM NTf2

Glass transition of glycerol in the volume-temperature plane

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